The main objective of this study was to find out the effect of laboratory and guided discovery strategies on attitude in geometry among senior secondary schools students in Katsina State, Nigeria. The quasi experimental group design was used. Two hundred and sixty five (265) sampled students were used from a total population of six thousand one hundred and fifty seven (6,157) students in the study area. Geometrical concepts attitude questionnaires was used as instrument for data collection in this research work. The data collected was analyzed and presented using mean and standard deviation and using Mann-Whitney (U-test) which appropriate when analyzing non-parametric data for only two (2) groups. Pretest result revealed that both experimental groups do not differ significantly in terms of their attitudes. However, posttest result revealed that experimental group one and two differ significantly in terms of their attitudes in favour of experimental group one. This shows that laboratory activity strategy has impact positively on student’s attitude in geometry. Based on the findings of this study, it was recommended that: mathematics teachers should be using mathematics laboratory in teaching and learning of geometry in their schools; parent teachers association and non-governmental organization can assist by providing laboratory and its equipment that will enable mathematics teachers to teach geometry using laboratory activity strategy; textbook publishers should publish textbooks that contain the guidelines and procedures for teaching geometry using laboratory activity strategy; curriculum developers and educational planners should emphasize the use of laboratory activity strategy as a solution to the problem of poor attitude of students in geometry in particular and mathematics in general. In addition, further research work on the use of laboratory activity strategy could be extended to junior secondary schools, tertiary institutions as well as to other areas of mathematics curriculum such as trigonometry, statistics, probability, algebra.