A medicament delivery device comprising: a housing; a needle cover movably placed at least partially in the housing; wherein the medicament delivery device further comprises a medicament container disposed within the needle cover and the housing; and a cap assembly configured to be mounted to the housing to cover a proximal opening of the housing, wherein the cap assembly comprises a locking member including a first engagement member configured to interact with the needle cover and the housing to limit a movement of the needle cover toward an inside of the housing, wherein the first engagement member is radially flexible and disposed between the housing and the needle cover; and a cap configured to engage the locking member and movably arranged in relation to the housing and the locking member between a first position in which the cap is engaged to the housing and a second position in which the cap disengages the housing; wherein the needle cover includes a second engagement member configured to engage the first engagement member when the cap is between the first position and the second position; wherein the second engagement member is a groove formed on the outer surface of the needle cover, and wherein the locking member further includes a stop cam disposed at the end of the first engagement member configured to rest within the groove of the needle cover; wherein the cap is further movably arranged between the second position and a third position in which the stop cam of the locking member disengages the groove of the needle cover and no longer limits the movement of the needle cover wherein the cap includes a third engagement member and the locking member includes a fourth engagement member, the third engagement member is configured to engage the fourth engagement member when the cap moves from the first position to the second position, and the third engagement member is configured to move the locking member away from the housing when the cap moves from the second position to the third position. a housing; a needle cover movably placed at least partially in the housing; wherein the medicament delivery device further comprises a medicament container disposed within the needle cover and the housing; and a cap assembly configured to be mounted to the housing to cover a proximal opening of the housing, wherein the cap assembly comprises a locking member including a first engagement member configured to interact with the needle cover and the housing to limit a movement of the needle cover toward an inside of the housing, wherein the first engagement member is radially flexible and disposed between the housing and the needle cover; and a cap configured to engage the locking member and movably arranged in relation to the housing and the locking member between a first position in which the cap is engaged to the housing and a second position in which the cap disengages the housing; a locking member including a first engagement member configured to interact with the needle cover and the housing to limit a movement of the needle cover toward an inside of the housing, wherein the first engagement member is radially flexible and disposed between the housing and the needle cover; and a cap configured to engage the locking member and movably arranged in relation to the housing and the locking member between a first position in which the cap is engaged to the housing and a second position in which the cap disengages the housing; wherein the needle cover includes a second engagement member configured to engage the first engagement member when the cap is between the first position and the second position; wherein the second engagement member is a groove formed on the outer surface of the needle cover, and wherein the locking member further includes a stop cam disposed at the end of the first engagement member configured to rest within the groove of the needle cover; wherein the cap is further movably arranged between the second position and a third position in which the stop cam of the locking member disengages the groove of the needle cover and no longer limits the movement of the needle cover wherein the cap includes a third engagement member and the locking member includes a fourth engagement member, the third engagement member is configured to engage the fourth engagement member when the cap moves from the first position to the second position, and the third engagement member is configured to move the locking member away from the housing when the cap moves from the second position to the third position.